President Obama had it absolutely right yesterday in Nevada when he said our immigration system no longer serves our nation’s interests — and now is the time for “common sense, comprehensive” reform. So we hope the president also meant it when he called on Washington “to find common ground and move forward in common purpose” to get us there.

We say this because there seems to be some doubt about his commitment. That would explain why the Senate’s “Gang of 8” — four Democrats and four Republicans — upstaged the president by announcing its own bipartisan proposal the day before he took up the issue.

If senators have their doubts, it may be because they know the man they are dealing with. The last time immigration reform was on the table, in 2007, it was because President George W. Bush and Sen. John McCain put it there, and Sen. Ted Kennedy worked with them in good faith to get a bill passed. As Obama noted yesterday, “You don’t get that match-up very often.”

So how did then-Sen. Barack Obama respond at the time? While claiming to support reform, he backed 11th-hour poison pills, such as an amendment introduced by Democrat Byron Dorgan to sunset a guest-worker provision important for GOP support. In the end, Sen. Obama’s vote for this mischievous amendment (in opposition to Kennedy) gave it its margin of victory.

Back then, Politico described the dynamics this way: “The biggest threats to an immigration bill spearheaded by Massachusetts Sen. Edward M. Kennedy have come from within: Twice this week, senators from his own Democratic Party were poised to back amendments that could have killed the fragile compromise.”

Weakened from within, the bill was fatally doomed when conservative opinion turned on Bush for supporting “amnesty.”

This time ’round, by contrast, reform has in its corner one of the conservative movement’s brightest stars, Florida Sen. Marco Rubio. Like Rubio, we recognize the hard work to be done on the details — e.g., securing the border, bringing in from the cold the 11 million illegals already here and instituting a guest-worker program. As we debate, we do well to remind ourselves of the goal: an immigration system that tackles illegality by offering a clear and lawful path for people of talent and enterprise.

We agree with the president: The moment and the momentum are now one.

We’d just point out that success in 2013 largely hangs on his willingness to make the compromises and show the leadership that Bush, Kennedy and McCain did back in 2007.